Does this patient have jumper's knee?

Jumper's knee, or patellar tendinopathy, is an inflammatory condition of the patella tendon that causes pain in the front of the knee. It is usually caused by repetitive overloading activities such as jumping.

Presentation

Patients usually have a history of sporting activities that overload the extensor mechanism of the knee such as basketball, volleyball, soccer and distance running.

They complain of pain in the front of the knee, just below the patella. In the early stages, patients do not have pain during their activities, but they have pain after them. As the condition becomes worse, they may have pain throughout activities as well.

Jumper's knee can be classified in 4 stages:

Stage 1: Pain only after activities.

Stage 2: Pain during activities, but still able to perform without limitations.

Physical exam

Tenderness to palpation of the patellar tendon, just inferior to the patella, is the hallmark of the diagnosis. A clinical pearl is to palpate the tendon with the knee in extension as opposed to flexion. Palpation in flexion may mask a subtle jumper's knee.

Patient may also have swelling of the tendon, and crepitus of the tendon with motion. Patients will also have pain with resisted knee extension.

A thorough knee exam including palpation of the joint lines, ligamentous and patellar stability, and range of motion should also be performed to rule out other pathology.

Differential diagnosis

Patellar tendon rupture

Can occur as acute injury. Patients will have sudden, severe pain in the front of their knee and their knee will buckle. A defect can usually be appreciated in the patellar tendon, though sometimes this is difficult to assess if severe swelling is present. Patient will not be able to perform a straight leg raise, and they will have an extensor lag (lack of full active extension in the setting of full passive extension).

X-rays will show patella alta (or high riding patella), and MRI will show the patellar tendon tear. Patients with patellar tendon ruptures should be placed in a knee immobilizer, and referred to an orthopaedic surgeon for urgent repair.

Patella fracture

Can occur as an acute injury. Patient will have pain over the patella itself. Diagnosis is usually made on x-ray. Place in a knee immobilizer and refer to an orthopaedic surgeon.

Patella chondromalacia (patellofemoral syndrome)

Presents with anterior knee pain. Pain is particularly bad with going up and down stairs. The pain with this condition is more proximal than with jumper's knee, and patients usually have no tenderness to palpation of the patellar tendon on exam. Most often this is a diagnosis of exclusion.

Meniscus tears

Will have pain along the joint line. The pain is usually more lateral or medial than jumper's knee, but on occasion the pain can be in the midline. Patients usually complain of clicking or popping in their knee. An MRI is diagnostic.

Fat pad syndrome

Inflammation of the fat pad that lies deep to the patellar tendon. Symptoms can be similar to jumper's knee, but pain is around the tendon, and not on it. This may represent a spectrum of jumper's knee and not a distinct entity. Regardless, the initial treatment is the same as that for jumper's knee.

Bone lesions

Tumors or infections are rare causes of anterior knee pain.

What tests to perform?

Radiograph

X-rays are usually negative for patients with jumper's knee. On occasion, the x-ray can show shadows consistent with soft tissue swelling around the patellar tendon. In chronic cases, the x-ray may show calcifications in the patellar tendon. X-rays are most useful for ruling out concomitant pathology.

Advanced imaging

An MRI is usually not necessary in the early stages of the disease when the diagnosis is obvious on clinical exam. For more severe or chronic cases, an MRI can show if there are tears in the patella tendon. MRI's are also most useful for ruling out concomitant pathology. For patients that cannot obtain an MRI, an ultrasound can also be diagnostic. However, an ultrasound will give limited information on intra-articular pathology.

How should patients with jumper's knee be managed?

Patients should refrain from activities that cause pain in order to rest the tendon and allow the inflammation to subside. Anti-inflammatories should be recommended if there are no contraindications.

Physical therapy should be prescribed to include eccentric training exercises, quadriceps strengthening, and hamstring stretching. Modalities such as massage, ultrasound, and iontophoresis with steroid creams may also be useful. Initial duration of therapy should be 6 weeks.

Patients may be advised to purchase a patellar tendon unloading brace that can be purchased at most pharmacies.

Second line treatment - steroid injection

For patients who do not experience pain relief with first line treatments, a steroid injection can be considered. However, there is a risk that the steroids can weaken the tendon, and promote rupture. Steroid injections for jumper's knee should be used sparingly.

Last line treatment - surgery

For patients who have failed at least 6 months of non-operative treatment, surgery can be considered. There are several techniques described, but all involve debridement of the pathologic tendon with reattachment of the normal tendon back to the bone.

Controversial treatment - platelet-rich plasma (PRP)

While there have been no well-designed clinical trials, several case series have reported positive results with PRP injections for jumper's knee. However, most insurers will not cover this procedure since it is still considered experimental.

Other treatments

Treatments such as shock-wave therapy, deep friction massage, ultrasound, acupuncture, and the injection of sclerosing agents have all been described in the literature for the treatment of jumper's knee.

There is mounting evidence that shock-wave therapy may be a useful modality. However, it is currently not readily available at most centers for this indication.

What happens to patients with jumper's knee?

Most patients have complete resolution of symptoms with non-operative treatment.

How to utilize team care?

Specialty consultations

An orthopaedic surgeon should be consulted if the patient is not improving with non-operative treatment, or has sustained a patellar tendon tear.